Method for chloridizing roasting of ores.



A. RAMN & KJ. J. BESKOW. METHOD FOR GHLORDIZING ROASTING' 0F OBES.

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i @hilili .ARTHUR RAMN AD KNTJT J'AKOB BESKCW, OF HELSINGBORG, SVJELEN. t

METHOD FOR CHLORIDZING RUASTING OF GRES.

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Application ilee Mey Z3, 1911.

.7h aller/m it may concern Be it known that we, ARTHUR llene): and

, Know' Jurion Biisiiow,*subjects or the King.;

of Sweden. residing at Villa lilargit, Olympia, I'lelsinghorg, and S. Storgatan 19, l'lclsingliorg. Sweden, have invented new and useful' mproveiuents in li/ iethods for Chloridizing Roasting of Orcs, of which the following is a specification.

ln chloridizing roasting' of ores, a process .which is generally performed, as is well known. byv treatin@a the ore, mixed with chlorids, (common salt), at roasting"tern peratu're while introducing atmospheric air, it has vbeen clithouit to heat the ore to the temperature required for the process. For this purpose, either rei'erheratory im# naceshave heen used, in which the ore has been heated ov its contact with combustion gases, or Inutile furnaces, in which the ore has received the vnecessary amount of heat through heated brick-Work surfaces. Both these methods possess disadvantages of differentl kinds. `When open reverheratory furnaces are used. the erases develoiied from the roasted material (the ore and the chloconcentration rid) are ymixed with combustion gases. As the-gases from the roasted material contain large quantities'oic hvdroclilori'c acid. sul,

furie acid. ete., which preferably should be condensed in as large quantities and as high and oureness as possible, it 1s .obvious that the mixing with the coi'nhustio'n cost has ybeen appliances in thev furnaces .more ntimatec'ontact between the 'gases is verv ohjectionable. r`liis disadvantage is'avoided' in usine inutile furnaces. but the latter. on the contrarie'fare unecouomical fas regardsheat, especially as the rouille Walls, which are had conductors of heatg vmust yhe of a considerable"thickness on account of the corrosive properties of the acid. gases and in vieivo' 'the required mechanical :strength ot the furnaces. A

The difiiculty of supplying heat 'for -the* use liv Whi ch Specicaton of Letters Patent.

have come intov 'atented. Jan. t2, ilg.

Serial No. 628,939.

caused thereby a. smaller quantity of aii` is required than in the hand-stirring furnaces and thus a reduced cooling action is obtained. it is also due'partly to the fact that on account of the speedy reaction the furnace dimensions can be 'made smaller, ,Whereby the loss `ol heat hv radiation. etc.. are essentially reduced. lf the aforesaid ditheulties in supplyingy heat are not as difficult to overcome in the future as at present. when chieiy hand-stirring furnaces are emploi/ed., it still remains a very desirable object to try to avoid the difficulties connected with the direct heating h v combustion gases as Well as with the heating in a. mullle in mechanicallv operated furnaces.

Accordingir to the present invention. by

Which the desired ohiect is attained the air required for the oxidation of the material to he roasted, is preheated to the roastingv temperature" whereby in mechanical furnaces, Where the reunir-ed simply of heat 1s comparatively small, a quantity of heat canbe supplied to'theore which is sufiicient',

with a suitable composition of the latter. to

maintain the roasting tia ted. v

The heatin.;f of the air previously to its introduction in the roasting; furnace should he effected hv means' of suiierheatcrs of such construction to prevent the air J'ro'm being mixed to any. Qfreat extent with the combustion gases servingY to heat the simerheater. l Forrsuch purpose, or channels can he used. which are heated from the outside ov combustion gases, While the air passes inside. or vice versa.

@if course it mav he advantageous to utiprocess when once inia 'svstem jot pines lise the heat contained. in the roasted ore by passim@ ain-over the same in a suecial com vpartaient or zone of the chloridiainsz furnace or outsidetlie said furnace. 'Theair thus someivhatpreheated ...is introduced 'in the superhea ter and finally When it has attained a suitable temperature inthe chloridizing. furnace or the comnartmcut or Zone of the same.' in which the chloridiz-ingf-nrocess' foes on or in ,which the supply'of heat is rehiirerl.

ift is obvious. that the combustion cases employed 'for heating thev air simerheuter, may he used. since only part of the heat contained has utilized in ythe superheater,

for directly drying or preheating the ore or mixture of chlorid and lore destined to be subjected to the chloridizing p'rocess.

ln'order that the present method may be fully understood an apparatus for carryingY out the same Will nowf be described with reference to the 1. accompanying drafgvinfr, where it is shown `in a tlong ritudinal vertical section.

l, 2, 3 are the different roasting'iearths, 4. the roof and 5 the mainfshaft of the furnace, said shaft carrying stirring arms 6. provided with obliquely set teeth 7 in .a known manner. The shaft 5 which is journaled in the bottom bearing `8 andiin the neck bearing` 9 is driven by means ofia toothed ,qear 10 and an intermediary shafgt 11 from the pulleys l2. The material llto be roasted enters through a channel lllprovided with an automatically closing,r check valvel 13 (with a counterweight 14) /filom a drying or preheat` ing device 16a 0n the bottom of the uppermost furnace chamber or compartment, the material in a knoufn manner is transported by the stir une,r me'chanismvfrom the center to the periphery w/here it falls down through y the openinf'rs 1T to the second compartment of, the chlpridizing furnace. In the said compartmpnt. the material is transported from the Iperiphery toward the center where it frills dlhwn through channels 19 provided with aut/omaticallv closing check valves 18 to the lowest compartment, from which the materia] i. .nally discharged through the channel QO/hhich is also provided withan autolleaiesthe box through the channel 15. The

material is fed intol the drying device from the feed hopper by a Worm-con'veyer 25 mounted in a casing 26 and driven by a pulley 27.

To thc side of the furnace is placed a superheater for air consisting of a system of pipes 28 surrounded by a brieloworlr structure 29 with ka furnace 30. The combastion gases from the furnace heat the pipes 28 and leave the superheater through the kpipe 31 discharging" into the preheater- 1G in. which the gases heat the material be fore they are led'olf to a chimney through the conduit 32. v

By means of a fan 33 air is blown through a pipe 34 into the cooling compartment 35, from Where it enters the pipes 28qthrough messie The arrangement thus described works in the following manner: The mixture of ere and chlorids 1s introduced by the Worm-conveyer 25 into the dryingr device 16: Where itl is heated by means of combustion gases from the superheater .29. Ilhen it falls down through the channei 15, into ythe chloridizing compartments 3S of the furnace where the reaction between the salt 'and the sulfur and metallic oxids et the ore takes place under the action oifthe air and the heat supplied by the hot air comingr from the pipes 2S together with the heat produced by the reaction itself. dJ/'hen the material leaves .the ehloridizing through the valvesal.y the reaction is practicaliy completed. In the cooling compartment 35. the material delirers part. of its heat to the air introduced lthere and leaves the furnace at a temperature which is not higher than is desirable for the following lixiriation. the fan 33 takes up a rather. large quantity of heat in the compartment 35 and is then further heated in the pipes 2 8, so that its temperature when enterincr the chloridiving'g1 compartment will be considerably high. The -i tnbustion gases from the furnace 30 first r ill heat the air indirectly in the pipes 28 and then the material to be roasted indirectlv in the preheater 16.

ln the way described. it is possible to supply the heatto the chloridizing compartment necessary for the reaction in 'an economical manner 'Without the' use of mutfies and without diluting the acid ,frases in the chloridizing compartment with combus tion gases. Y

llavine now partieularlv described the nature of our invention and the manner of its operation. what we claim is:-

l. A process for chloridizing roasting' of ores. consistingr in feedingY a mixture of ore and ehloridiingj means from one compartment to another in a furnace. stirring the, mixture. heating: air independently of the furnace by means of fuel in superheatcr so arranged that the `air is'not'mixed 'with Ifuel in a suoerheater so arranged that the air is'not mixed with the combustion gases of the fuel, and introducing said air into compartments I The air forced in by means of the compartment Where the chloridizin process takes place.

3. A process for chloridizing roasting` of ores, consisting in feeding a mixture of ore and chloridizing means from one compartment to another in a furnace, stirring the mixture, heating;n air independently of the furnace by means of fuel in aJ superheater so arranged that the air is not mixed with the products of comhustion of the fuel, preheating,lr new quantitles of ore by means of said products of combustion previously to 

